Breathable multi-layer barrier fabrics of various combinations of layered material are disclosed in prior art patents. U.S. Pat. No. 4,041,203, issued Aug. 9, 1977, to Brock et al., discloses a fabric made up of a mat of generally discontinuous thermoplastic microfibers as a top layer and a web of substantially continuous, randomly deposited polymer filaments as a bottom layer, the layers being bonded at intermittent discrete regions. A three-layer fabric having a mat layer on the outside and a web layer in the middle is also disclosed. The specific polymer materials used for the mat and the web include polyolefins such as polypropylene. U.S. Pat. No. 4,828,556, issued May 9, 1989, to Braun et al., discloses a multi-layer fabric having a first layer of porous melt-blown material, a second layer comprised of a non-microporous film of polyvinyl alcohol, and a third layer of porous non-woven material in the form of a spun-bonded or melt-blown web. The fabric of this reference is said to be useful for absorbent articles such as diapers. Numerous prior patents directed to microporous films are also disclosed and discussed in this reference. Impervious, absorbent barrier fabrics are disclosed in U.S. Pat. No. 4,379,192, issued Apr. 5, 1983, to Wahlquist et al., the fabric including layers having continuous filament webs, microfiber mats, and polymeric film, the mats providing an uncompacted absorbent center layer.
In addition, various orientated microporous films are presented in U.S. Pat. No. 4,867,881, issued Sep. 19, 1989, to Kevin E. Kinzer, which discloses a microporous article comprising a thermoplastic polymeric structure having a plurality of cells with adjacent cells being interconnected by passageways to provide a network of communicating pores with the structure being orientated in at least one direction. Laminated structures of these same microporous materials are presented having at least one other material laminated to the microporous film are disclosed is U.S. Pat. No. 4,539,256, issued Sep. 3, 1985, to Gene H. Shipman. Porous film composites are disclosed in U.S. Pat. No. 5,169,712, issued Dec. 8, 1992, to William T. Tapp wherein porous film composites having at least one layer of an orientated polymeric porous film comprised of ethylene-propylene co-polymers and other specific polymer requirements are disclosed. While numerous combinations of layers of various polymeric materials prepared in a desired physical form are disclosed in these references in combination with microporous films, the combination of an inner layer of microporous film and outer layers of non-woven materials which are thermally bonded into a composite fabric having minimum strength, vapor permeability and body fluid barrier capabilities as disclosed herein are not known to have been disclosed or suggested by the prior art.
Other porous film composites are disclosed in the Japanese Patent Application, Kokai, No. 63-276533, publication date Nov. 14, 1988, inventors Kawano et al., entitled "Laminated Film". The Japanese reference "Laminated Film" does not provide a liquid barrier in fact presents a filtered-type product which readily flows liquid and would be suitable for example as a separator in an electrochemical cell. A breathable non-woven composite barrier fabric for protective garments should provide for wear comfort by enabling passage of water vapor resulting from perspiration or humidity in the environment, as well as forming a barrier to passage of body fluids such as blood. For effectiveness in situations involving handling of patients, the barrier should be effective at elevated pressure to prevent the blood from being projected or soaked through the fabric. In addition, strength and durability are a necessity in the fabric as exemplified by breaking strength as defined by ASTM D751 (Grab Method) and Mullen burst test values.